Fix some glitches in shortcuts and split-handling

* get rid of contraproductive Ctrl-W to close a tab. Replaced that with Ctrl-Shift-W. Use 
  nano in qterminal and try to search. You
  will see, what i mean ...
* it takes a horizontal ruler to tile a terminal vertically and
  vice versa
* make border of active terminal a litte bit thinner 3px -> 2px